The invention relates to a screen element, especially for the filtration of liquid or gaseous materials.
In DE 195 37 269 a screen element is disclosed; it is disposed in an intake tube in an internal combustion engine. The element is composed of metal wire and has the purpose of making the flow of intake more uniform and thereby provide for noise reduction. Such screen elements are usually made by laying a piece of prefabricated screen into an injection molding machine and there injection molding a mounting ring around it. Since a certain stability of the screen element is necessary, metal is preferably used for the screen area.
Screen elements of the kind named above are used in all areas of technology. Due to the demand for a certain stability of shape, materials of great stiffness are basically preferred.
The disadvantage in the use of such materials is that, for the sake of great stiffness the material must have a certain thickness. The disadvantage thus arises that the resistance to flow is increased due to the greater use of material.
It is the object of the invention to avoid the aforementioned disadvantages and provide a sieve or screen element which has low resistance to flow but at the same time is of stable shape.
This object is achieved by the invention as described and claimed hereinafter.
The substantial advantage of the invention is that a mesh web can be used as material for the screen element, which may not be stable in shape, but does have a low resistance to flow. Stability of shape is achieved by the fact that the mesh web is attached to a supporting skeleton. This supporting skeleton can be composed of a thermoplastic synthetic resin and can be configured according to the application, that is, it can be optimally adapted to the application. It is also possible to use thermosetting plastics or elastomers for making the supporting skeleton.
In one preferred embodiment of the invention the supporting skeleton is attached to the mounting ring or mounting element. Thus its stability of shape is increased.
In accordance with a further embodiment of the invention the mesh web is a synthetic fabric and is made from monofilament or multifilament fibers. To increase the effective area of the screen element, any desired free-form surfaces or ruled surfaces can be chosen. Such a screen element is suitable for various media, such as air, water, fuel, oil or the like, and can be used both in automobile manufacture and in medicine or in general apparatus construction.
An advantage in the use of a mesh web is great elasticity, and indeed in both the longitudinal and transverse directions. This elasticity prevents damage to the screen element in case of severe loading.
A method for producing a screen element for filtering liquids or gases with a mounting ring and holding element, and a sieve or screen filter disposed thereon, has the following steps: A mesh fabric is placed as a screen filter into a production machine and can be imbedded by injection molding in a supporting skeleton and a mounting ring and holding element of thermoplastic synthetic resin. The mesh fabric can be a knit, and in a preferred embodiment of the invention, can be fed to the molding machine from a strip and then severed from this strip to deposit a length of fabric in the mold cavity.
Additional features of preferred embodiments of the invention will be found not only in the claims but also in the description and the drawings, and the individual features can be realized each by itself or together in the form of subcombinations in embodiments of the invention and in other fields, and may constitute advantageous as well as independently patentable embodiments, for which protection is hereby claimed.